CN108475981B

CN108475981B - Wind turbines with superconducting generators with improved thermal insulation

Info

Publication number: CN108475981B
Application number: CN201680075085.7A
Authority: CN
Inventors: 安德斯·瓦明·雷布斯多夫; 莫恩斯·克里斯滕森; 斯特凡·A·艾森
Original assignee: Envision Energy Denmark ApS
Current assignee: Far East Energy Technology Plc; Envision Energy Co Ltd
Priority date: 2015-12-21
Filing date: 2016-11-22
Publication date: 2021-01-22
Anticipated expiration: 2036-11-22
Also published as: CN108475981A; ES2962631T3; EP3394967B1; DK3394967T3; WO2017108042A1; EP3394967A4; PT3394967T; US20180375419A1; EP3394967A1; US10971989B2

Abstract

The present invention relates to a wind turbine having a generator comprising a rotor rotatably arranged relative to a stator and a method of assembling a generator thereof. The rotor includes a plurality of superconducting pole units disposed on a back iron, which is separated from the rotor structure by a plurality of insulating panels or beams. The plate or beam is located between the two ends of the rotor and is oriented with respect to the direction of rotation of the rotor. Each plate has a first end fixedly connected to another first beam extending in the axial direction and a second end fixedly connected to another second beam also extending in the axial direction. The first beam is further securely connected to the back iron, while the second beam is further securely connected to the rotor structure. The insulation panels or beams provide a flexible, inexpensive support interface that can accommodate tolerances of the various components.

Description

Wind turbine with superconducting generator having improved thermal insulation structure

Technical Field

The invention relates to a wind turbine with a superconducting generator and an assembly of a superconducting generator thereof, wherein the generator comprises a rotor rotatably arranged relative to a stator, the rotor comprising a back iron thermally insulated from the rotor structure, the rotor further comprising a plurality of pole units arranged relative to the back iron, each pole unit comprising a rotor coil made of a superconducting material, the stator comprising a plurality of pole units having a stator coil, wherein the rotor coil is arranged to interact with the stator coil via an electromagnetic field upon rotation of the rotor relative to the stator.

Background

Superconducting generators are known that thermally separate the warm rotor structure from the cold superconducting pole units in order to minimize the amount of cooling required to cryogenic operating temperatures. This in turn enables the cooling capacity of the cooling system to be reduced.

EP 2521252a1 solves this problem by providing the superconducting pole units in a separate stepped cryostat, which is in turn provided directly on a supporting back iron connected to the rotor structure. This configuration provides a complex and expensive solution, increasing the overall assembly time. This design also requires supportably disposing a superconducting coil in each cryostat, which further increases the complexity of this solution.

US 2008/0079323a1 discloses an alternative in which superconducting coils are supportably disposed within a cradle-like back iron. The back iron is also maintained below the critical temperature of the superconducting material. The cold back iron is separated from the warm rotor structure by a plurality of hot support blocks. The cold back iron is also connected to the rotor structure by means of heat insulated bolts. The individual bolts and support blocks add complexity and cost to this solution. This configuration also requires precise alignment of the support blocks to enable the back iron to be correctly placed so that the bolts can be mounted to the rotor structure.

Accordingly, there is a need for an improved insulating support structure that allows for simple and inexpensive installation of back iron.

Disclosure of Invention

Object of the Invention

It is an object of the present invention to provide a support structure which solves the above mentioned problems.

It is an object of the present invention to provide a support structure that can accommodate tolerances of various components.

It is an object of the present invention to provide a support structure that provides improved thermal insulation between the rotor structure and the back iron.

It is an object of the present invention to provide an assembly method which allows a fast and simple mounting of the back iron.

Disclosure of Invention

One object of the invention is achieved by a wind turbine comprising:

-a wind turbine tower,

-a nacelle arranged on top of a wind turbine tower,

a rotatable hub arranged opposite the nacelle, the hub being connected to at least two wind turbine blades,

a generator rotatably connected to the hub, wherein the generator comprises a rotor rotatably arranged with respect to a stator, the rotor comprising a back iron and a rotor structure, the rotor further comprising at least one pole unit arranged with respect to the back iron, the at least one pole unit comprising at least one rotor coil made of a superconducting material, the stator comprising at least one pole unit comprising at least one stator coil,

wherein the at least one rotor coil is arranged to interact with the at least one stator coil via an electromagnetic field when the rotor rotates relative to the stator, wherein the rotor further comprises at least one support element arranged between the back iron and the rotor structure, the at least one support element comprising a first end connected to the back iron and a second end connected to the rotor structure, wherein the at least one support element is made of a thermally insulating material, characterized in that the back iron comprises a side surface facing the rotor structure, the rotor structure comprises a corresponding side surface facing the back iron, wherein the first end is connected to the side surface and the second end is connected to the corresponding side surface, wherein the first end and the second end extend in an axial direction defined by the rotor.

The terms "plate" and "plate-like element" are defined as a plate having a length and width that is at least four times the thickness of the plate. The plate forms two large side surfaces having any suitable surface profile, including a planar profile, a curved profile, a corrugated profile, or any other suitable surface profile. The terms "beam" and "beam-like element" are defined as a beam having a length and a width, wherein the width is no more than four times the thickness of the beam.

This provides a simple and inexpensive mounting of the back iron and rotor structure and also improves the thermal insulation between the cold back iron and the warm rotor structure. The heat shield also provides a flexible mounting interface that can accommodate the tolerances of the various components, allowing for a simpler and faster assembly process. In contrast to conventional mounting schemes using tie rods, no movable ball and socket arrangement is required, and therefore no movable parts are located within the vacuum chamber.

The rotor structure and a housing connected to the rotor structure form a closed chamber, wherein a back iron and a superconducting pole unit are arranged in the chamber. The housing may be formed from a front or outer wall, an end wall and, optionally, an intermediate rear or inner wall portion. The rotor structure, e.g. the yoke thereof, may form at least a part of the rear or inner wall of the housing. The wall parts may be firmly connected, for example by gluing or welding, or mounted together, for example by bolts or screws. Sealing means such as deformable rubber elements or welding may be used to form a gas-tight seal between the respective wall portions. Thus, the housing forms a closed chamber that can be evacuated to form a vacuum chamber. In an example, the thickness of the housing, such as the thickness of its walls, may be between 1mm and 20mm, for example between 5mm and 10 mm.

The present arrangement is suitable for any type of wind turbine comprising a generator, wherein the rotor and optionally the stator comprise superconducting coils. The use of the heat shield reduces the total amount of cold side, i.e. the superconducting pole unit and back iron, which in turn reduces the cooling capacity required by the cooling system. The panel also allows for an inexpensive and simple manufacturing process compared to conventional insulated tension rods.

The rotor and the stator extend in an axial direction defined by a central rotational axis of the generator. The rotor and the stator also extend in a radial direction perpendicular to the axial direction. The back iron has two ends facing in opposite axial directions and a side surface facing the rotor structure. Likewise, the rotor structure has two ends facing in opposite axial directions and a side surface facing the back iron. The back iron of the rotor is spaced from the rotor structure by a plurality, i.e. at least two, of support elements located between the two ends of the rotor. The number of support elements may be selected based on the particular configuration and size of the generator. In an example, the number of such support elements may be between 3 and 20, such as between 5 and 12, such as 8 or 10. In an example, the spacing between the back iron and the rotor structure may have any suitable radial length, for example up to 500mm, for example between 100mm and 300 mm. This allows the cold back iron to be thermally isolated from the warm rotor structure. This space may be evacuated to further isolate the cold parts from the surrounding warm parts.

According to one embodiment, the at least one support element is oriented relative to the direction of rotation of the rotor, wherein the at least one support element extends from its first end towards its second end substantially in the same direction as the direction of rotation of the rotor.

Each support element has a first end facing a side surface of the back iron and a second end facing a side surface of the rotor structure, wherein the first and second ends extend in an axial direction. The support element is disposed at a first angular position with respect to a tangential direction of the side surface of the back iron. The support element is also placed in a second angular position with respect to the tangential direction of the side surface of the back iron, for example parallel to the tangential direction. The first and second angles are measured along a line extending through the first and second ends of the respective support elements. In an example, the first angle may be between 20 and 80 degrees, such as between 25 and 60 degrees, such as between 30 and 40 degrees. In an example, the second angle may be between 0 and 80 degrees, such as 20 and 60 degrees. This allows the support elements to be oriented substantially in the same or opposite direction of the rotor rotation direction. This also allows torque and other forces to be transferred from the back iron and thus from the superconducting pole unit to the rotor structure.

The support elements may be distributed along the side surface of the rotor structure around the circumference of the rotor structure. Alternatively, one or more of these support elements may be defined by a set of support elements aligned in the axial direction. Each set may comprise a plurality of individual support elements, i.e. at least two, with their respective ends aligned with each other in the axial direction. This allows the support elements to be formed as a single continuous support element or a group of individual support elements. This enables the support element to be more easily handled during assembly.

Optionally, the rotor may further comprise one or more support elements arranged relative to the support elements described above. In an example, the further support elements are symmetrically positioned with respect to the support element such that they extend in substantially opposite directions with respect to the support element. The further support element and the support element described above may form a single V-shaped support element, wherein the first end is defined by an intermediate area located between the two second ends, and vice versa. Alternatively, the further support element and the support element may be separate support elements. These further support elements also allow torque and other forces to be transferred from the back iron and thus the superconducting pole unit to the rotor structure.

According to one embodiment, at least one beam-like element is provided at least one of the first end and the second end, wherein the at least one beam-like element extends in the axial direction.

In an example, the support element may be shaped as a plate, and a plurality of beams, i.e. at least one may further be provided on one or both side surfaces of the rotor structure and the back iron. The number of beams may correspond to the number of plates.

Alternatively, one or more of these beams may be defined by a set of individual beams aligned in the axial direction. The number of the middle beams in each group can correspond to the number of the middle plates in each group. The first beam is disposed at a first end of the panel and the second beam is disposed at a second end of the panel. Each beam is arranged to connect a respective plate to the back iron or rotor structure.

When installed, each beam extends in an axial direction and has a first end facing the respective plate and an opposite end facing away from the respective plate. Each beam also has at least one side surface (in the axial direction) facing the back iron or rotor structure. Optionally, each beam also has another side surface facing in the opposite direction as a contact surface for contacting a corresponding side surface of the back iron or rotor structure.

The beam has a length measured in an axial direction and a width measured between the first and second ends, e.g. in a tangential direction. The tangential direction is perpendicular to the axial and radial directions of the rotor and stator. The thickness of the beam is measured between two side surfaces or between a side surface of the back iron or rotor structure and a side surface of the beam. In an example, the thickness and/or length of the beam is equal to or greater than the respective thickness and/or length of the plate or set of plates.

According to one embodiment, at least one of the first end and the second end and the at least one beam-like element are firmly connected by means of a mounting means or an adhesive means.

The beam may form part of the rotor structure and/or the back iron, e.g. the yoke of the rotor structure, and the beam may thereby project outwardly from a side surface of the rotor structure or the back iron. This allows the beam to be formed in the same manufacturing process as the rotor structure or back iron. This reduces the overall assembly time and the number of assembly steps required. Alternatively, the beam may form a separate element, which may be firmly connected to the rotor structure or the back iron. In this configuration, the side surfaces of the rotor structure and/or back iron also serve as contact surfaces for contacting the respective side surfaces of the beams. Alternatively, the lateral surface of the rotor structure and/or the back iron may comprise a plurality of preset areas, which are prepared to receive and fix the respective beam. In an example, one or more of these regions may comprise recesses and/or holes for mounting beams as described below, the recesses being arranged to follow the shape of the respective beam. Each region defines a connection point that allows the beam to be selectively positioned in one or more regions.

The beam may be mounted to the rotor structure and/or back iron using mounting means, such as bolts and optional nuts, screws, or other suitable mounting means. The beam may comprise a first set of through holes arranged to receive the mounting means. Likewise, the rotor structure and/or back iron may include a plurality of corresponding apertures, such as through holes, configured to receive mounting means as described above. Alternatively or additionally, the beam may be bonded to the rotor structure and/or back iron using a bonding means, such as glue or other suitable bonding means. The specific bonding means/glue may be chosen such that it has high bonding properties to the material of the rotor structure, back iron and/or beam. In an example, the bonding device/glue may be a two-part epoxy-based resin, for example

2015. This allows the respective beam to be firmly connected to the rotor structure and/or the back iron. The beams may also be securely connected by other means, such as welding.

Each beam may also include a second set of holes, such as through holes, arranged to receive other mounting means for mounting the respective plate to the beam. These mounting means may be a bolt and optionally a nut, screw, pin or other suitable mounting means. The wet laminate of the boards may in an example be positioned relative to these holes in the respective beams, and the pins may be pushed through the wet laminate before it cures. This allows the fibers in the laminate to be pushed aside without breaking. This in turn increases the strength of the plate around the hole formed by the pin, particularly when subjected to tensile forces. Alternatively, a sleeve may be inserted into the aperture of the plate and optionally bonded to the plate to increase structural strength. This allows the beam and the corresponding plate to be securely connected by using the mounting means.

Alternatively or additionally, the beams may be bonded to the respective plates using bonding means, such as glue or other suitable bonding means. The specific adhesive means/glue may be chosen such that it has high adhesive properties to the material of the rotor structure and/or the beam. In an example, the bonding device/glue may be a two-part epoxy-based resin, for example

2015. The adhesive means/glue is applied on one or more contact surfaces of the beam and/or a corresponding number of contact surfaces of the plate. This creates a suitable bond between the plates and the beam, allowing the beam and the respective plate to be securely attached.

The first set of holes may be provided on the end faces of the first and second ends, while the second set of holes may be provided on the aforementioned side surfaces. Alternatively, both the first and second sets of holes may be provided on the side surface, for example in two different rows.

According to one embodiment, at least one of the first end and the second end and the at least one beam-like element are firmly connected by a combination of mounting means and adhesive means.

Optionally, the plate and the beam are connected via a combination of mounting means and adhesive means. The beam and the rotor structure may further be connected via a combination of mounting means and adhesive means. This provides a strong connection capable of transferring loads and forces, such as compressive and tensile forces, between the back iron and the rotor structure. This also allows the individual components to remain securely connected even if the adhesive fails, for example, due to cracking or adhesive failure.

According to one embodiment, the at least one beam-like element forms part of at least one of the first end and the second end.

The first and/or second beam may instead form part of the respective plate, for example as thickened first and/or second ends. In this configuration, the second set of holes may be omitted and the mounting means may be inserted into another second set of holes of the respective beam. Sleeves may be inserted into these holes and optionally bonded to the respective beams to increase structural strength. Alternatively, the first and/or second beams may be securely attached to the back iron and/or rotor structure by suitable pins or threaded rods that push through the wet laminate of the respective beams prior to curing. This allows the fibers in the laminate to be pushed aside without breaking, which in turn increases the beam structural strength around the hole formed by the pins or threaded rods.

Alternatively or additionally, adhesive means, such as glue or other suitable adhesive means, may be used in this configuration to adhere the respective beam to the back iron and/or rotor structure. The specific adhesive means/glue may be chosen such that it has a high adhesion to the material of the respective beam, back iron and/or rotor structure. In an example, the bonding device/glue may be a two-part epoxy-based resin, for example

2015. The adhesive means/glue is applied to one or more contact surfaces of the beam and/or a corresponding number of contact surfaces of the rotor structure or back iron. This forms a suitable bond between the respective beam and the back iron or between the respective beam and the rotor structure.

According to one embodiment, the at least one beam-like element comprises at least one stress relief element, such as a stress relief groove, arranged to reduce stress in the at least one beam-like element.

Optionally, the first and/or second beam may comprise a plurality of stress relief elements, i.e. at least one, arranged to reduce stress in the respective beam caused by thermal deformation of the beam. The stress relief elements may be provided as stress relief grooves formed in one or both side surfaces of the respective beam. Other shapes may be used to relieve thermal stress of the beam. Each stress relief element may extend in an axial direction and may be arranged in one or more rows. This reduces stress in the beam caused by thermal deformation of the beam.

According to one embodiment, one of the at least one beam-like element and at least one of the first end and the second end has a tapered end facing the other of the at least one beam-like element and the at least one of the first end and the second end, wherein the other of the at least one beam-like element and the at least one of the first end and the second end has a corresponding end shaped to receive the tapered end.

The respective beam and panel may be arranged to form at least one lap joint defined by at least a first end of the beam and a respective end of the panel. At least one of the first end of the beam and the respective end of the plate may include at least one projection extending toward the opposite facing end. At least one other of the respective end of the plate and the first end of the beam may include at least one respective groove or recess arranged to receive such a projection. Alternatively, both ends of the beam and the plate may comprise at least one protrusion and at least a corresponding groove or recess. The protrusions and corresponding grooves or recesses both form at least two oppositely facing contact surfaces. The above-described adhesive means/glue may be applied to one or more of these contact surfaces. This increases the total surface area between the two ends, allowing for a stronger bond between the respective beam and the plate.

The first end of the beam may be wedge-shaped, wherein the thickness of this wedge-shaped end decreases towards its end surface. Alternatively, one or more of the above-mentioned protrusions may be wedge-shaped, wherein the thickness thereof decreases towards the end surface thereof. The corresponding groove or recess may thus follow the contour of this wedge. This distributes the stresses in the beam and the panel more evenly and prevents the stresses from concentrating at the lap joint.

Optionally, the respective beam may further form another lap joint defined by the second end of the beam and the respective end of the further panel. This allows the ends of both plates to be connected to the same beam. Alternatively, the grooves or notches may be omitted and areas of the plate or ends of the plate may be sandwiched between the beam and the back iron or, instead, between the beam and the rotor structure. The beam and plate area/plate end are then mounted and/or glued to the back iron or to the rotor structure. Alternatively, if no separate beam is used, the plate area and the overlapping plate end may be mounted and/or bonded directly to the back iron or to the rotor structure.

According to one embodiment, the at least one support element comprises at least one reinforcing element extending between a first end and a second end.

One or more of the plates may comprise a plurality of reinforcing elements, i.e. at least one, arranged to increase the stiffness of the respective plate in operation. The reinforcing element extends from the first end to the second end and vice versa. The reinforcing element may form part of the plate or be securely attached to the plate by mounting, gluing, welding or other techniques. In examples, the reinforcing elements may be corrugated, serrated, trapezoidal elements, stiffeners, or other suitable reinforcing elements. The reinforcing elements may be outwardly convex on one or both side surfaces of the plate. This increases the structural strength of the panel and prevents it from bending due to pressure.

According to one embodiment, the at least one support element is made of a fibre-reinforced material, such as fibre-reinforced plastic.

The support element is any insulating material or composite material having low thermal conductivity. In an example, the support element is made of a fiber reinforced material, such as Fiber Reinforced Plastic (FRP). The fibers may be organic fibers, carbon fibers, glass fibers, or other suitable fibers. The beams may be made of the same material or composite material as the support elements, or of a different material or composite material. The beams may be made of metal, such as aluminum or steel, or composite materials, such as fiber reinforced plastic, or other suitable materials or composites thereof. In an example, the materials of the support member, the beam and the optional adhesive means/glue may be chosen such that they have the same or at least substantially the same thermal deformation properties in one or more directions.

The material of the support element, e.g. the plate or the composite material, is chosen such that it has sufficient structural strength, while it is able to accommodate, for example, tolerances of bending to the individual components and thermal shrinkage of the cold back iron relative to the warm rotor structure. This allows the manufacturing and assembly process to be cheaper and simpler than the traditional solutions using insulating rods.

The length of the support element is measured in the axial direction and the width is measured between the first end and the second end, for example in a combined radial and tangential direction. The thickness of the support element is measured between the side surfaces facing the back iron and the rotor structure. In an example, the length may be up to 1500mm, for example between 800mm-1200 mm. In an example, the width may be up to 3800mm, for example between 500mm-2500 mm. In an example, the thickness may be between 10mm-50mm, such as 20mm-40mm, or even greater than 50mm, as described below. The thickness may be measured at a central portion located between the two ends or at one of the ends.

The back iron and rotor structure may be made of any suitable material or alloy, such as steel, iron (e.g., FeNi), or other suitable material or alloy.

According to one embodiment, the at least one support element is made of a first layer sandwiched between at least two second layers, wherein one of the first layer and the at least second layer has a stronger structural strength than the other layers.

The support element, e.g. a plate, may have a sandwich structure comprising a first layer and at least a second layer. In an example, the panel may include a central/first layer and at least outer/second layers on both sides of the central/first layer. The first layer may be arranged to provide thermal insulation to the panel and the second layer arranged to provide structural strength to the panel, or vice versa. The first and second layers may have the same or different thermal insulation properties. This allows the panel to have suitable structural strength while acting as a thermal barrier between the warm and cold beams.

According to one embodiment, the plurality of support elements are arranged opposite to each other in the axial direction defined by the rotor.

Instead of using a single continuous support element, a plurality of support elements may be used, arranged in the axial direction between the back iron and the rotor structure, and aligned with respect to each other. Each individual support element has a first end facing the back iron and a second end facing the rotor structure. This divides the total contact area between the respective support element and the back iron or between each respective support element and the rotor structure into a plurality of individual contact areas. This also provides a strong support structure with a reduced surface area for each support element.

According to one embodiment, at least one mounting element is provided on at least one of the first end and the second end of each of the plurality of support elements, wherein the at least one mounting element is securely connected to at least one of the back iron and the rotor structure.

One or more mounting elements may be provided on the first end and/or the second end of a single plate rather than a beam. In an example, a first mounting element may be disposed at a first end of each plate and a second mounting element may be disposed at a second end of each plate. The mounting element is made of metal, such as aluminium or steel, or a composite material, such as fibre reinforced plastic, or other suitable material or composite thereof. This allows a single plate to be securely attached to the back iron and/or rotor structure.

Alternatively, the first and/or second mounting element may form part of the respective plate, for example as a thickened first end and/or second end. This allows the mounting element to be manufactured in the same process as the board.

When mounted, each mounting element extends in an axial direction and has a first end facing the respective plate and an opposite end facing away from the respective plate. Each mounting element also has at least one side surface (radial direction) facing the back iron or rotor structure. Optionally, each mounting element also has another side surface facing in the opposite direction as a contact surface for contacting a corresponding surface of the back iron or rotor structure.

According to one embodiment, the plurality of support elements comprises at least one first support element and at least one second support element, wherein the at least one first support element extends from its first end towards its second end substantially in one direction relative to the direction of rotation of the rotor, and the at least one second support element extends from its first end towards its second end substantially in the opposite direction.

The individual support elements, such as plates, may be oriented relative to the direction of rotation of the rotor such that they all extend in substantially the same or opposite direction of rotation. Alternatively, the first support element may extend substantially in the same direction of rotation and the second support element may extend substantially in the opposite direction of rotation. The first and second support elements may lie in the same tangential plane or be angled relative to each other in a radial plane. In an example, the first support element may be positioned at any angle between 0 degrees and 180 degrees relative to the second support element.

One or both ends of the first and second support elements may be aligned tangentially such that their respective first and/or second mounting elements are aligned along a common axis. This reduces the overall amount of machining of the back iron and/or rotor structure. Alternatively, one or both ends of the first and second support elements may be offset in a tangential direction relative to each other such that their respective first mounting elements are aligned along one axis and their respective second mounting elements are aligned along another parallel axis. This allows the length of the first and second support elements and thus the thermal insulation of the support elements to be optimized.

The first and second support elements may be further offset in the axial direction relative to each other or aligned with each other in a radial plane. The respective first or second mounting element of the first and second support elements may be formed as a single mounting element or as separate mounting elements. If they are radially aligned, the first and second support elements may form a single support element extending through the intermediate mounting element as either the first or second mounting element.

According to one embodiment, the plurality of support elements comprises a first set of support elements and at least a second set of support elements, wherein at least one of the support elements of the first set intersects at least one of the support elements of the at least second set.

Individual support elements, such as plates, may further be arranged in groups along the circumference of the rotor structure. The individual groups may be arranged relative to each other such that they cross each other. In an example, the first plate of one group and the second plate of an adjacent group may be arranged such that they cross each other at a point of intersection, and vice versa. This also allows the length of the individual plates to be optimized to achieve minimal heat conduction and thereby improve thermal insulation. This further allows the plates to be placed at an optimal angle to the rotor structure, which allows for optimal force transfer and saves rotor material.

According to one embodiment, the plurality of support elements comprises a first set of support elements and at least a second set of support elements, wherein the at least one mounting element of the first set and the at least one mounting element of the at least second set are aligned along a common axis.

Alternatively, individual support elements, such as plates, may be positioned relative to one another such that they do not cross one another. In an example, the first plate of one group and the second plate of an adjacent group are positioned relative to each other such that their respective first and/or second ends are substantially aligned along a common axis, e.g., a common axis defined by the respective mounting elements. This also allows the use of shorter plates and the back iron and/or rotor structure requires less machining. This also enables a quicker and easier mounting of the insulation laminate around the panels and optionally the mounting elements, e.g. wrapping the insulation laminate, since the panels do not cross each other.

The thermal barrier laminate may include at least one layer of polyethylene, polyester or other suitable support material and at least one layer of reflective material, such as aluminum, as a mirror that resists thermal radiation. In an example, commercially available super insulating films or laminates may be used.

According to one embodiment, the at least one mounting element is firmly connected to at least one of the back iron and the rotor structure by means of a mounting means or an adhesive means or a combination thereof.

The respective mounting element may be firmly connected to the support element, back iron and/or rotor structure using the mounting means and/or adhesive means as described above. In an example, the mounting element may have a set of holes or through-holes arranged to receive mounting means, such as bolts or screws. The back iron and/or rotor structure may also be configured to receive the mounting device. Alternatively, the mounting means may be pre-tensioned to ensure a secure connection between the respective mounting element and the back iron or between the respective mounting element and the rotor structure.

The back iron and/or the rotor structure may comprise a plurality of protrusions, i.e. at least one protrusion, on the respective side surface. Each protrusion may extend in the axial direction and may protrude outward from the corresponding side surface. Each projection may have at least one contact surface for contacting a corresponding contact surface on a single mounting element. The individual mounting elements can then be firmly connected to the respective projections. Alternatively, the first end of the respective mounting element may be placed at an angle, for example between 20 and 80 degrees, with respect to the tangential direction of the corresponding side surface of the back iron or rotor structure. The single mounting element can then be firmly attached directly to the side surface of the back iron or rotor structure without using protrusions.

According to one embodiment, the at least one mounting element is firmly connected to the at least one support element by at least one pin connection.

Alternatively, the mounting elements may be securely connected to the respective support elements either by one or more pin connections. The support element, e.g. the first and/or second support element, may comprise at least one through hole, e.g. two or more, extending in axial direction for receiving and fixing the pin. The first and/or second end of the support element may comprise one or more protruding elements in which the through-hole is located. The mounting element, e.g. the first and/or second mounting element, may comprise at least one, e.g. two or more complementary protruding elements extending towards the support element. The raised elements and complementary raised elements may be shaped as a joint or plate member. The pin may include means for locking the pin in place, such as a hole for receiving a locking pin, a bolt head, a threaded coupling for mounting a nut, or other suitable locking means. This enables the first and second support elements to rotate during operation while transferring shear loads in radial and tangential directions to the back iron or rotor structure.

The mounting element may further comprise one or more hollows for saving material and weight. In an example, one cutout may be provided opposite the pin such that the height of the pin coupling, i.e. the axis of rotation, can be lowered towards the side surface of the back iron or rotor structure. This reduces the moment arm and requires less material for transferring the load to the back iron or rotor structure, respectively.

When installed, a pre-tension may be applied to the individual pin connections to limit shrinkage as the cold component cools. The first mounting element may be provided as a common mounting element for the first and second plates, wherein the protruding elements of both plates are connected to the same pin. This reduces the total number of mounting elements.

The shape of the mounting element can be optimized so that the load can be optimally transferred to the back iron or the rotor structure. This may be accomplished by providing the mounting element with one or more fingers that may then be mounted or bonded to the back iron or rotor structure by increasing the bonding surface area between the individual mounting/bonding points or areas or by increasing the distance. In an example, the mounting element may include at least four fingers or fingers extending outwardly from the mounting element in a tangential and/or axial direction. This reduces the weight of the mounting element and saves material.

According to a particular embodiment, the thickness of the at least one support element is between 80mm and 120 mm.

The support element may have an increased thickness at the first end and/or the second end compared to the thickness of the central portion. This increases the structural strength around the through hole. This also reduces the risk of delamination of the support element, which may lead to failure of the pin connection. Alternatively, the support element may have a constant thickness along its entire length, i.e. the thickness of the end portions and the central portion is the same. Optionally, the support element may have one or more hollows provided in the side surface for saving material and weight. This prevents the support element from bending due to compressive forces during operation.

Alternatively, the support element may be shaped as a beam, wherein the beam may be firmly connected to the respective mounting element, for example by the above-mentioned pin connection. In an example, the thickness of the beam, for example measured at one end, is between 80 and 120 mm. In an example, the length of the beam is between 180mm and 220 mm. This allows reducing the number of support elements while increasing the contact area per support element.

The required structural strength of the laminate at the first and/or second ends may be achieved by providing individual fibre plies around the dowel pins or rods which define the through holes. The pin or rod is removed after curing. Alternatively, after curing, the through-holes may be drilled on the first end and/or the second end. Optionally, a sleeve may be provided in the through hole to increase structural strength. Other known techniques may be used to provide the required structural strength.

One object of the invention is achieved by a method of assembling a wind turbine generator as described above, wherein the method comprises the steps of:

providing a generator rotor, wherein the rotor comprises at least a rotor structure,

the rotor back iron is arranged opposite to the rotor structure,

at least one support member position is determined relative to the rotor structure and back iron,

mounting a first end of the at least one support element to a back iron and further mounting a second end of the at least one support element to a rotor structure.

The present arrangement allows for a simple and inexpensive assembly process of the rotor which minimizes the total amount of cooling required. The present assembly method also provides a flexible mounting of the back iron and the rotor structure that does not require very precise alignment of the individual components and is able to accommodate tolerances of the individual components. Unlike conventional methods, no ball and socket arrangement is required in the vacuum chamber to mount the chill onto the rotor structure.

The use of plates to insulate the back iron from the rotor structure allows for better thermal isolation between cold and warm components. No insulating blocks or insulating bolts and corresponding recesses are required. Cold components, such as back iron and superconducting pole units, can be manufactured separately and optionally assembled with warm components, such as rotor structures, housings, and drive shafts.

According to one embodiment, at least one support element is arranged between a side surface of the back iron and a corresponding side surface of the rotor structure, wherein the at least one support element is angled with respect to a tangential direction of at least one of the side surface and the corresponding side surface.

A support element, such as a plate or a beam, is located between the two ends of the rotor and is oriented with respect to the direction of rotation of the rotor such that the first end and the second end extend parallel to the axial direction of the rotor. The support element may thus extend in a combined radial and tangential direction. The individual support elements or groups of support elements are disposed in an angled position such that the first and second ends are radially offset with respect to each other. The support elements thereby act as spokes and allow torque and other forces to be transferred from the back iron, and thus from the superconducting pole unit to the rotor structure. The load transmitted from the superconducting pole unit, for example in the case of a short circuit of the superconducting pole unit, is also transmitted to the rotor structure via these plates. The back iron may have an outer diameter of 2000mm to 4000mm, for example between 2500mm to 3500 mm.

The rotor structure may form part of the drive shaft or be mounted to the drive shaft. The rotor structure may include a yoke facing the back iron and an inner support facing the drive shaft. The yoke and inner support may be formed as a single piece or joined by using mounting means (e.g., bolts and nuts), welding, or other suitable techniques. The inner support may comprise one or more reinforcing elements and, optionally, one or more hollows. This reduces the weight of the rotor, saving material of the rotor.

The thickness of the back iron and/or yoke, measured in the radial direction, may be up to 120mm, for example between 50mm and 100mm, for example between 70mm and 80 mm.

According to one embodiment, the first or second end is mounted to the back iron or the rotor structure before the back iron is arranged relative to the rotor structure.

One or more of the support elements may be positioned relative to and securely connected to the respective rotor structure or back iron. The back iron may then be located in its installed position and any remaining support elements may then be positioned relative to the back iron or rotor structure and ultimately securely connected to the back iron or rotor structure. This allows the support element to be used to guide the back iron into alignment with the rotor structure.

After the back iron and the superconducting pole units are installed, the remaining housing may be mounted to the rotor structure. The rotor structure, e.g. its yoke, may serve as a rear wall of the housing, which is mounted to either end of the end wall, e.g. via an intermediate rear wall portion. The end wall may further be mounted to a front wall located between the back iron and the stator. A vacuum system can be used to evacuate the enclosed chamber defined by the outer housing. This forms a vacuum chamber in which the superconducting pole units are located, wherein the vacuum space also provides thermal insulation between the cold parts and the warm parts surrounding the cold parts, such as the outer casing and the rotor structure.

Finally, electrical and cold connections may be coupled to the superconducting pole unit, which enables the superconducting coil to be cooled to cryogenic operating temperatures. The superconducting coils are arranged to interact with a plurality of corresponding stator coils of pole units located in the stator via electromagnetic fields when the rotor rotates relative to the stator. Cold components, such as superconducting coils, may operate at cryogenic operating temperatures between 10K and 70K. The warm parts, such as the rotor structure, may operate at ambient temperatures, such as between 250K and 350K.

According to one embodiment, the method further comprises the steps of:

-arranging at least one beam-like element on at least one of the side surface and the corresponding side surface, and determining the position of at least one of the first, second end with respect to said at least one beam-like element.

One set of first beams may for example be provided in a plurality of predetermined areas on a side surface of the back iron and/or another set of second beams may be provided on a corresponding side surface of the rotor structure. The first and second beams may be aligned parallel to the axial direction. This may be done before or after the back iron is positioned and aligned with the rotor structure.

Each plate may then be positioned relative to each of the first and second beams to enable the back iron to be attached to the rotor structure. This may be done after the back iron is placed in its installed position. The beams and/or plates may be slid into place in either the axial or tangential directions. The back iron may be placed in a pre-installation position relative to the rotor structure, wherein the beam and the plate may be used to guide the back iron into its final installation position. This reduces the complexity of the assembly process and also reduces the overall assembly time, as compared to other conventional assembly methods, since very precise alignment back irons are not required to install the insulating support elements.

One or more further plates may be arranged opposite the above-mentioned plates and connected to the back iron and the rotor structure via separate first and second beams. In an example, these further plates are symmetrically positioned with respect to the above-mentioned plate such that they extend substantially in opposite directions. Alternatively, these further plates may be connected to the same first and/or second beam as the plates described above. These further plates may also act as spokes and allow torque and other forces to be transferred from the back iron and thus the superconducting pole unit to the rotor structure.

According to one embodiment, the at least one beam-like element and at least one of the first and second ends are firmly connected by using mounting means and/or adhesive means.

The first and second beams may be securely attached to the back iron and the rotor structure, such as the yoke thereof, by using suitable mounting and/or adhesive means. This may be done before or after the back iron is placed in its installed position. The first and second beams may be mounted before moving the back iron into position relative to the rotor structure, as this allows easy access to the beams and, optionally, their mounting means.

The first and second beams may further be securely connected to the respective plates by using suitable mounting and/or adhesive means. This can be done before, during and after the back iron is moved to its final installed position. The panels may be installed by using adhesive means such that the respective beams and panels form lap joints.

Alternatively, the method further comprises the steps of:

at least one beam-like element is securely connected to at least one of the first end and the second end and is placed in position relative to at least one of the side surfaces and the corresponding side surfaces prior to mounting the at least one support element to the back iron and the rotor structure.

In this configuration, the first and second beams may be securely attached to the single panel during or after the manufacturing process of the panels. The back iron may then be placed in its installed position relative to the rotor structure. The plates on which the beams are mounted can then be positioned relative to the back iron and rotor structure and securely attached to the back iron and rotor structure. This allows the panel and the first and second beams to be pre-assembled prior to installation.

According to one embodiment, the step of determining the position of the at least one support element comprises arranging a plurality of support elements in an axial direction defined by the rotor.

During assembly, the plurality of support elements may be arranged in an axial direction and oriented with respect to a rotational direction of the rotor. In an example, 2 to 15, such as 5 plates to 10, such as 3 or 4 support elements are arranged in the axial direction. These support elements may be placed at an angle with respect to the tangential direction of the back iron and the side surface of the rotor structure, as described above. This allows for a quick and simple handling and determination of the position of the individual support elements. This also provides a strong support structure with a reduced total surface area which reduces heat transfer between the rotor structure and the back iron.

According to one embodiment, the method further comprises the steps of:

-providing at least one mounting element on at least one of the first and second ends of each of the plurality of support elements.

The single plate, e.g. the support element, may in an example be provided with one or more mounting elements, e.g. at the time of manufacture or after manufacture of the plates. The mounting element may be securely attached to the plate using mounting means and/or adhesive means as described above. The first mounting element of the respective plate is then positioned with respect to the lateral surface of the back iron, for example on a projection thereof, and is firmly connected to the back iron. The second mounting elements of the respective plate are then positioned with respect to the lateral surface of the rotor structure, for example on the projections thereof, and are firmly connected to the rotor structure.

According to a particular embodiment, the at least one mounting element is securely connected to at least one of said first and second ends by at least one pin connection.

Alternatively, the mounting element may alternatively be securely connected to the support element, e.g. the plate, using a pin connection as described above. This allows for an earlier mounting, since the mounting element and the support element can be positioned separately and firmly connected. This also allows an earlier mounting of the insulating laminate or membrane, since the support element can be at least partially covered by this laminate or membrane before or after being connected to the mounting element.

The first and second mounting elements may be securely connected to the back iron and the rotor structure, respectively. The back iron is then moved, for example in the axial direction, to its final position relative to the rotor structure. A single support member, such as first and second support members, may then be positioned relative to the first and second support members and the pins may be inserted into the through holes of the mounting member and the end of the plate.

Alternatively, the first mounting element is fixedly connected to the back iron or the second mounting element is fixedly connected to the rotor structure. The individual support elements are then positioned and connected to these mounting elements via pins. The other mounting elements are further securely connected to the single support element via pins. The back iron is then moved, for example in the axial direction, to its final position relative to the rotor structure. The other mounting elements are then securely connected to the back iron or rotor structure.

In another option, the first mounting element is fixedly connected to the back iron or the second mounting element is fixedly connected to the rotor structure. The back iron is then moved, for example in the axial direction, to its final position relative to the rotor structure. The single support element is then connected to the other mounting elements via pins. The plate with the other mounting elements is then positioned relative to the back iron or rotor structure and securely connected to the back iron or rotor structure and the already securely connected mounting elements.

According to one embodiment, the method further comprises the steps of:

-positioning the at least one first support element with respect to the direction of rotation of the rotor such that it extends substantially in one direction,

and the number of the first and second groups,

-positioning the at least one second support element relative to the at least one first support element such that it extends substantially in opposite directions.

Each individual support element, e.g. a plate or a beam, is oriented with respect to the direction of rotation of the rotor, e.g. in the same or opposite direction. In an example, the first support element is arranged at an angle with respect to the tangential direction of the back iron or rotor structure such that it extends substantially in the direction of rotation. The second support element is further arranged at an angle with respect to the tangential direction of the back iron or rotor structure such that it extends substantially in the opposite direction. The first and second support elements may be arranged in an alternating order or in groups along the axial direction. The first support element may further be positioned at an angle to the second support element in a radial plane or the same tangential plane. This allows the arrangement and position of the first and second support elements to be selected according to the particular configuration of the rotor.

In the determination of the position of the first and second support elements, the second mounting elements of these support elements may be offset in the axial and/or radial direction with respect to each other. This allows the first and second support elements to be mounted or dismounted separately. Alternatively, the second mounting elements of the support elements may be aligned with each other in the axial and/or radial direction. This allows the first and second support elements to be mounted and dismounted in pairs.

According to one embodiment, at least one of the plurality of support elements intersects at least one other support element.

The first and second support elements may form a set of support elements extending in the axial direction. A plurality of groups may be arranged along the circumference of the rotor structure. In an example, the number of sets may be between 3 and 20 sets, such as between 6 and 16 sets, such as between 9 and 12 sets. In an example, a first plate of a group may be positioned such that it intersects a second plate of an adjacent group. The second plates of this group may be further positioned such that they intersect the first plates of another adjacent group. The intersection between the first and second plates may be located between the first and second ends of the respective plates. This allows the distance, e.g. chord, between the first ends of the first and second plates to be increased compared to using a single continuous plate as described above.

This in turn provides an optimal force transfer between the back iron and the rotor structure and saves material for the rotor structure.

The first and second plates may be spaced apart so that they do not accidentally rub against each other and thereby cause accelerated wear during rotation of the rotor.

According to one embodiment, at least one of the support element, the at least one beam-like element and the at least one mounting element is manufactured by using pultrusion or extrusion.

The various support elements described above may be manufactured by extrusion, pultrusion, or other suitable manufacturing processes. This reduces the amount of dressing work, such as grinding and polishing. This also reduces the amount of broken fibres in the laminate of the support element. Alternatively, a single support element may be cut to the desired size using a larger support element.

Likewise, the beams and/or mounting elements for securely connecting the support element to the back iron or rotor structure may be manufactured by extrusion, pultrusion, or other suitable manufacturing processes. The beams and/or mounting elements may then be machined to their finished configuration using various machine tools. Or the beams and/or mounting elements may be formed during the manufacturing process of the panel.

The present invention is not limited to the embodiments described herein, and thus the embodiments can be combined in any manner without departing from the object of the present invention.

Drawings

The invention is illustrated by way of example only and with reference to the accompanying drawings, in which:

FIG. 1 illustrates an exemplary embodiment of a wind turbine;

FIG. 2 illustrates an exemplary embodiment of a generator in a wind turbine;

FIG. 3 shows a first embodiment of the rotor of the generator shown in FIG. 2;

FIG. 4 shows a cross-sectional view of the back iron and rotor structure;

FIG. 5 illustrates a first embodiment of a first beam;

FIG. 6 shows a first embodiment of a second beam;

FIG. 7 shows a second embodiment of a corresponding beam;

FIG. 8 shows a third embodiment of a corresponding beam;

FIG. 9 shows a fourth embodiment of a corresponding beam;

FIG. 10 shows three embodiments of lap joints between respective beams and panels;

FIG. 11 shows three other embodiments of the lap joint shown in FIG. 10;

FIG. 12 shows a second embodiment of a rotor of a generator;

FIG. 13 illustrates the plate and mounting member shown in FIG. 12;

FIG. 14 shows a cross-sectional view of the rotor shown in FIG. 12;

fig. 15 shows the rotor shown in fig. 12 viewed in the axial direction;

FIG. 16 shows a first embodiment of assembling a generator rotor;

FIG. 17 illustrates a second embodiment of assembling a generator rotor;

FIG. 18 shows a third embodiment of the plate and mounting element of the rotor shown in FIGS. 16-17;

fig. 19 shows a fourth embodiment of the generator rotor.

In the following, the drawings will be described one by one, and the same numerical references will be used in different drawings for the different components and positions shown in the drawings. All of the components and locations shown in a particular figure are not necessarily discussed with that figure.

List of location labels

1 wind turbine

2 Tower frame

3 ground base

4 nacelle

5 wheel hub

6 wind turbine blade

7 electric generator

8 stator

9 rotor

10 pole unit with superconducting coils

11 back iron

12 rotor structure

13 side surface of rotor structure

14 side surface of back iron

15 support element, plate

16 first end of plate

17 second end of plate

18 direction of rotation

19 first beam

20 second beam

21 first end of the beam

22 second end of the beam

23 side surface of the beam

24 mounting device

25 beam groove

26 bonding device

27 pin

28 casing tube

29 raised element

30 receiving the recess of the protruding element

31 support element, plate

32 first mounting element

33 second mounting element

34 through hole of first mounting element

35 through hole of second mounting element

36 guard iron projection

37 rotor structure projection

38 first plate

39 second plate

40 raised element, plate element

41 through hole

42 pin

43 refers to

44 first beam, support element

45 second beam, support element

Detailed Description

Fig. 1 shows an exemplary embodiment of a wind turbine 1. The wind turbine 1 comprises a wind turbine tower 2 arranged on a foundation 3. The nacelle 4 is arranged on top of the wind turbine tower 2 and arranged to be yawed relative to the wind turbine tower 2 by a yaw system (not shown). A hub 5 is rotatably arranged relative to the nacelle 4, wherein at least two wind turbine blades 6, here three wind turbine blades are shown, are mounted to the hub 5. The hub 5 is connected to a rotating machine in the form of a generator (shown in fig. 2) which is arranged in the nacelle 4 by means of a drive shaft for generating a power output.

Fig. 2 shows an exemplary embodiment of a generator 7 connected to the hub 5. Here, for illustrative purposes, only the central rotational axis of the drive shaft is shown (shown in dotted lines). The generator 7 comprises a stator 8 and a rotor 9 which is rotatably arranged relative to the stator 8. The stator 8 comprises a plurality of pole units (shown in dotted lines) having stator coils arranged to interact with rotor coils located in the plurality of pole units 10.

At least the rotor coils are made of a superconducting material operating below its critical temperature. Thus, at least the pole unit 10 acts as a superconducting pole unit. The stator coils are made of an electrically conductive material, such as copper, and operate at ambient temperature.

Fig. 3 shows a first embodiment of the rotor 9, in which the pole units 10 are arranged on the back iron 11, facing the stator 8, for example on the outer side surface (shown in fig. 3). A cooling system (not shown) is used to cool the pole unit 10 to a cryogenic operating temperature between 10K and 70K.

The rotor 9 further comprises a rotor structure 12 with an inner support facing the drive shaft and a yoke facing the back iron 11. The inner support is here shaped as a disc with one or more hollows, as shown in fig. 2. The inner support is mounted to the drive shaft using a mounting device. The yoke is here shaped as a ring or tubular element having a side surface 13 facing the back iron 11. The back iron 11 is also shaped as a ring or tubular element having a side surface 14 facing the rotor structure 12.

The back iron 11 is separated from the rotor structure 12 by a plurality of support elements 15 arranged between the side surfaces 13, 14. The support element is shaped as a plate 15 made of a heat insulating material, such as Fibre Reinforced Plastic (FRP), which insulates the back iron 11 from the rotor structure 12. The rotor structure 12 operates at ambient temperatures between 250K and 350K. Each plate 15 has a first end 16 facing the back iron 11 and a second end 17 facing the rotor structure 12.

Fig. 4 shows a cross-sectional view of the rotor structure 12 and back iron 11. Here, the pole unit 10 is omitted for the purpose of illustration. The plate 15 is positioned with the first and second ends 16, 17 extending in an axial direction, as shown in fig. 2 and 3. The plates 15 are further oriented such that they extend in a combined radial and tangential direction, and thus, substantially in the same direction as the direction of rotation 18 of the rotor 9, as shown in fig. 4.

A first beam 19 is provided at the first end 16 of the plate 15 and a second beam 20 is provided at the second end 17 of the plate 15. The first beam 19 and the second beam 20 extend in the axial direction along the side surfaces 13, 14, as shown in fig. 3, 4. A first beam 19 is fixedly connected to the back iron 11 and the first end 16 of the plate 15. The second beam 20 is firmly connected to the rotor structure 12 and the second end 17 of the plate 15.

Fig. 5 shows a first embodiment of the first beam 19 having a first end 21 facing the plate 15 and a second end 22 facing in the opposite direction. The first beam 19 also has two side surfaces 23 facing opposite in the radial direction, one of which also acts as a contact surface for contact with the side surface 14, for example in a predetermined area thereof. Here, the first end 21 is placed in a first angular position with respect to the tangential direction of the side surface 14, for example between 20 and 80 degrees.

The first beam 19 comprises a first set of through holes for receiving mounting means 24 in the form of bolts and nuts for securely connecting the first beam 19 to the back iron 11. The back iron 11 comprises a corresponding set of through holes for mounting means 24, as shown in fig. 4.

Fig. 6 shows a first embodiment of a second beam 20 having a first end 21' facing the plate 15 and a second end 22 facing in the opposite direction. The second beam 20 also has two side surfaces 23 facing opposite in the radial direction, one of which also acts as a contact surface for contact with the side surface 13, for example in a predetermined area thereof. Here, the first end 21' is placed in a second angular position, for example parallel to the tangential direction of the side surface 13.

The second beam 20 comprises a first set of through holes for receiving mounting means 24 in the form of bolts for securely connecting the second beam 20 to the rotor structure 12. The rotor structure 12 includes a corresponding set of through holes for mounting the device 24, as shown in fig. 4.

At least one slot 25 is formed in the first ends 21, 21' of the first and

second beams

19, 20 to receive the first and second ends 16, 17 of the plate 15, as shown in fig. 5 and 6. One or more of the inner surfaces of the respective slots 25 may act as contact surfaces for contacting one or more corresponding surfaces on the respective ends 16, 17 of the plate 15. Adhesive means 26 in the form of glue is applied to these contact surfaces to securely connect the plate 15 to the first and

second beams

19, 20. Alternatively, the

respective beam

19, 20 comprises a second set of through holes for receiving mounting means 24 in the form of bolts and nuts, or the first set of through holes of the

respective beam

19, 20 is also used for securely connecting the plate 15 to the

respective beam

19, 20, as shown in fig. 4.

Fig. 7 shows a second embodiment of the

respective beam

19, 20, wherein a second set of through holes is arranged to receive further mounting means 27 in the form of pins. The pins are pushed through the wet laminate at the respective ends 16, 17 of the plate 15 so that the fibres in the laminate are pushed aside without breaking. This in turn enhances the structural strength of the plate 15 around the through-hole formed by the pin.

Fig. 8 shows a third embodiment of a

respective beam

19, 20, which beam forms part of the plate 15'. In this configuration, the respective ends 16 ', 17 ' defining the beam have an increased thickness compared to the remainder of the plate 15 '. Sleeves 28, such as metal sleeves, are placed in the first set of through holes to increase the structural strength of the plate 15' around these through holes. The plate 15' is then firmly connected to the back iron 11 or the rotor structure 12 via the mounting means 24.

Fig. 9 shows a fourth embodiment of a

respective beam

19, 20, which beam forms part of the plate 15'. This configuration differs from the embodiment of fig. 7 in that the respective ends 16 ', 17 ' have the same thickness as the remainder of the plate 15 '. The mounting means 24 can then be inserted into these sleeves 28 'to firmly connect the plate 15' to the back iron 11 or the rotor structure 12.

Fig. 10 shows three embodiments of lap joints between the

respective beams

19, 20 and the respective ends 16, 17 of the plate 15.

In fig. 10A, the

respective beams

19, 20 have a rectangular cross-sectional profile, viewed in the tangential direction. The respective ends 16, 17 of the plate 15 and therefore the slot 25 also have a rectangular profile.

In fig. 10B, the beams 19 ', 20' have a wedge-shaped cross-sectional profile, viewed in the tangential direction. The thickness measured between the side surfaces 23 ' decreases from the second end 22 ' to the first end 21 '. The respective ends 16, 17 of the plate 15 and therefore the slot 25 have a rectangular profile.

In fig. 10C, the respective ends 16 ", 17" of the plate 15 "and thus the groove 25 'have a wedge-shaped cross-sectional profile, and the groove 25' has a corresponding oppositely-directed wedge-shaped cross-sectional profile, viewed in the tangential direction. The thickness measured between the side surfaces of the plate 15 "decreases towards the edges of the ends 16", 17 ", as shown in fig. 10C.

Fig. 11 shows three other embodiments of lap joints between

respective beams

19, 20 and respective ends 16, 17 of the plate 15. In these configurations, the

respective beam

19, 20 and plate 15 each comprise at least one raised element 29 and at least one slot 30 arranged to receive an opposite raised element 29.

In fig. 11A, the raised elements 29 and the grooves 30 have a rectangular profile, viewed in the tangential direction. Likewise, the

respective beams

19, 20 have a rectangular profile.

In fig. 11B, at least one of the raised elements 29 'of the respective beams 19 ", 20" has a wedge-shaped profile and at least one of the respective grooves 30' has an inverted wedge-shaped profile. The thickness of this wedge-shaped protruding element 29' decreases towards the edge of the element, as shown in fig. 11B. The respective beams 19 ", 20" have a wedge-shaped cross-sectional profile, as shown in fig. 10B.

Fig. 12 shows a second embodiment of the rotor 9' of the generator 7, wherein a plurality of support elements 31 are arranged in the axial direction. The support member 31 is shaped as a plate 31, made of an insulating material, such as Fiber Reinforced Plastic (FRP). Each plate 31 is firmly connected to the back iron 11' via a first mounting element 32. Each plate 31 is also firmly connected to the rotor structure 12' via a second mounting element 33. Here, five plates 31 in the axial direction are shown. For illustrative purposes, only the yoke of the rotor structure 12' is shown here.

Fig. 13 shows the plate 31 and its mounting

elements

32, 33. The plate 31 is made of a heat insulating material, such as Fibre Reinforced Plastic (FRP), which insulates the back iron 11 'from the rotor structure 12'.

The mounting

elements

32, 33 have a first end facing the plate 31 and a second end facing in the opposite direction. The mounting

elements

32, 33 also have two oppositely facing side surfaces, one of which also serves as a contact surface for contacting a side surface of the back iron 11 'or the rotor structure 12'.

The first and second mounting

elements

32, 33 are arranged to securely connect the plate 31 to the back iron 11 'and the rotor structure 12'. The first mounting element 32 comprises a set of through holes 34 for receiving mounting means in the form of bolts for securely connecting the first mounting element 32 to the back iron 11'. The back iron 11' comprises a corresponding set of through holes (not shown) for receiving the mounting means. The second mounting element 33 comprises a set of holes 35 for receiving mounting means in the form of bolts for securely connecting the second mounting element 33 to the rotor structure 12'. The rotor structure 12' includes a corresponding set of through holes (shown in fig. 14) for receiving mounting means.

Fig. 14 shows a cross-sectional view of the rotor 9 ' in which the mounting

elements

32, 33 are positioned relative to

projections

36, 37 on the side surfaces 13 ', 14 ' of the back iron 11 ' and the rotor structure 12 '.

Each first mounting element 32 of the plate 31 is firmly connected in the axial direction to a projection 36 on the lateral surface 14 'of the back iron 11', as shown in fig. 12, 14. The mounting means of the first mounting element 32 can be reached from a substantially radial direction, as shown in fig. 12 and 14.

Each second mounting element 33 of the plate 31 is firmly connected in the axial direction to a projection 37 on the side surface 13 'of the rotor structure 11', as shown in fig. 12, 14. The mounting means of the second mounting element 32 can be reached from a substantially tangential direction, as shown in fig. 12 and 14.

Fig. 15 shows the rotor 9 'viewed from the axial direction, wherein the first plate 38 is positioned such that it extends substantially in the same direction as the direction of rotation 18 of the rotor 9'. The second plate 39 is positioned such that it extends substantially in the opposite direction to the direction of rotation 18 of the rotor 9'. The first and

second plates

38, 39 are offset in the axial direction relative to each other as shown in fig. 14. The second mounting elements 33 of the first and

second plates

38, 39 are further offset in the axial direction relative to each other as shown in fig. 14, 15.

Viewed in the axial direction, the adjacent first and

second plates

38, 39 form a set located at the circumference of the rotor structure 12'. Here, six sets of first and

second plates

38, 39 are shown along the circumference of the rotor structure 12. The first plate 38 in this group is positioned in assembly so that it intersects the second plate 39 of the adjacent group, as shown in figure 15.

Fig. 16 shows a first embodiment of a method of assembling a rotor 9 "according to the invention. First, the rotor structure 12 is provided. A plurality of second mounting elements 33' are provided on the lateral surface 13 and are firmly connected to the rotor structure 12. The plurality of first and second plates 38 ', 39 ' are then positioned relative to the second mounting element 33 ' and securely connected via a first pin connection (shown in fig. 18). The first plurality of mounting elements 32 ' are positioned relative to the first and second plates 38 ', 39 ' and are securely connected via a second pin connection (shown in fig. 18). The back iron 11 is aligned and moved into position relative to the rotor structure 12. The first mounting element 32' is then firmly connected to the back iron 11.

The rotor coils are placed on the back iron 11 before or after the back iron 11 is moved into position.

Fig. 17 shows a second embodiment of a method of assembling the rotor 9 ". In this embodiment, the second mounting element 33' is provided on the side surface 13 and is firmly connected to the rotor structure 12. The back iron 11 is then moved into position relative to the rotor structure 12. The first and second plates 38 ', 39' are firmly connected to respective first mounting elements 32 'separate from the rotor 9', as shown in fig. 17. The first and second plates 38 ', 39' and the first mounting element 32 'are then arranged on the lateral surface 14 and are firmly connected to the back iron 11 and to the second mounting element 33', respectively. Only a predetermined area of the back iron 11 for receiving the first and second plates 38 ', 39 ' and the first mounting element 32 ' is shown here.

Fig. 18 shows a third embodiment of the rotor 9 ", in which the first and second mounting elements 32 ', 33' are different from the first and second mounting

elements

32, 33. Here, only a cross-sectional view of the rotor 9 "is shown. In this embodiment, the mounting elements 32 ', 33' have at least two projecting elements 40 extending radially outwardly from the base. The bottom is arranged for mounting and/or gluing to the back iron 11 or the rotor structure 12. Each protruding element 40 has a through hole 41 extending in the axial direction for receiving and securing a removable pin 42.

Another through hole 41 is provided at the first and second ends of each plate 38 ', 39'. This through hole 41 also extends in the axial direction and is arranged to receive and fix a pin 42. The pin 42 is connected to the first and second plates 38', as shown in fig. 16 and 17.

One or both of the mounting elements 32 ', 33' optionally have a plurality of fingers 43 extending in a tangential direction, as shown in fig. 18. Here, the fingers 43 are shown only on the first mounting element 32'. The fingers 43 are arranged to be mounted and/or glued to the back iron 11 or the rotor structure 12 for optimal transfer of load.

Fig. 19 shows a fourth embodiment of the rotor 9 "' in which the support elements are different from the

plates

15 and 31. In this embodiment, the support element is shaped as a beam, made of an insulating material, such as Fibre Reinforced Plastic (FRP). Each beam has a constant thickness along its length.

The first and second support elements or

beams

44, 45 include a plurality of plate members or knuckles, e.g., one, two or more, distributed along the width of the respective first and second ends, as shown in fig. 19. Each plate member or knuckle has a through hole 41 for receiving and securing a pin 42. The first and second mounting elements 32 ", 33" may further include at least one attachment projection element, such as a plate element or knuckle, for added support. The pin 42 further extends through this additional protruding element.

Claims

1. A wind turbine, comprising:

-a wind turbine tower,

-a nacelle arranged on top of the wind turbine tower,

-a rotatable hub arranged opposite the nacelle, said hub being connected to at least two wind turbine blades,

-a generator rotatably connected to the hub, wherein the generator comprises a rotor rotatably arranged with respect to a stator, the rotor comprising a back iron and a rotor structure, the rotor further comprising at least one pole unit arranged with respect to the back iron, the at least one pole unit comprising at least one rotor coil made of a superconducting material, the stator comprising at least one pole unit having at least one stator coil, wherein the at least one rotor coil is arranged to interact with the at least one stator coil via an electromagnetic field when the rotor rotates with respect to the stator, wherein the rotor further comprises at least one support element arranged between the back iron and the rotor structure, the at least one support element comprising a first end connected to the back iron and a second end connected to the rotor structure, wherein the at least one support element is made of a thermally insulating material, characterized in that the back iron comprises a side surface facing the rotor structure, the rotor structure comprising a corresponding side surface facing the back iron, wherein the first end is connected to the side surface and the second end is connected to the corresponding side surface, wherein the first end and the second end extend in an axial direction defined by the rotor, wherein the at least one support element extends in the axial direction defined by the rotor and is arranged at an angle with respect to a tangential direction of at least one of the side surface and the corresponding side surface.

2. A wind turbine according to claim 1, wherein the at least one support element is oriented relative to the direction of rotation of the rotor, wherein the at least one support element extends from the first end towards the second end substantially in the same direction as the direction of rotation of the rotor.

3. A wind turbine according to claim 1 or 2, wherein at least one beam-like element is provided on at least one of the first and second ends, wherein the at least one beam-like element extends in an axial direction.

4. A wind turbine according to claim 3, wherein at least one of the first and second ends is securely connected to at least one beam-like element by mounting means or adhesive means.

5. A wind turbine according to claim 4, wherein at least one of the first and second ends is securely connected to at least one beam-like element by a combination of mounting means and adhesive means.

6. A wind turbine according to claim 3, wherein the at least one beam-like element forms part of at least one of the first and second ends.

7. A wind turbine according to claim 3, wherein the at least one beam-like element comprises at least one stress relief element arranged to reduce stress in the at least one beam-like element.

8. The wind turbine of claim 7, wherein the at least one stress relief element is a stress relief groove.

9. The wind turbine of claim 1, wherein one of the at least one of the first and second ends and the at least one beam-like element has a tapered end facing the other of the at least one of the first and second ends and the at least one beam-like element, wherein the other of the at least one of the first and second ends and the at least one beam-like element has a corresponding end shaped to receive the tapered end.

10. The wind turbine of claim 1, wherein the at least one support element comprises at least one reinforcing element extending between the first and second ends.

11. The wind turbine of claim 1, wherein the at least one support element is made of a fiber reinforced material.

12. The wind turbine of claim 11, wherein the fiber reinforced material is fiber reinforced plastic.

13. The wind turbine of claim 1, wherein the at least one support element is made of a first layer sandwiched between at least two second layers, wherein one of the first layer and the at least second layer has greater structural strength than the other layers.

14. The wind turbine of claim 1, wherein the plurality of support elements are disposed opposite each other along an axial direction defined by the rotor.

15. The wind turbine of claim 14, wherein at least one mounting element is disposed on at least one of the first end and the second end of each of the plurality of support elements, wherein the at least one mounting element is securely connected to at least one of the back iron and the rotor structure.

16. A wind turbine according to claim 14 or 15, wherein the plurality of support elements comprises at least one first support element and at least one second support element, wherein the at least one first support element extends from its first end towards its second end substantially in one direction with respect to the direction of rotation of the rotor and the at least one second support element extends from its first end towards its second end substantially in the opposite direction.

17. The wind turbine of claim 14, wherein the plurality of support elements comprises at least a first set of support elements and at least a second set of support elements, wherein at least one of the first set of support elements intersects at least one of the at least second set of support elements.

18. The wind turbine of claim 14, wherein the plurality of support elements comprises at least a first set of support elements and at least a second set of support elements, wherein at least one mounting element of the first set is aligned with at least one mounting element of the at least second set along a common axis.

19. The wind turbine of claim 15, wherein the at least one mounting element is securely connected to at least one of the back iron and the rotor structure by a mounting device, an adhesive device, or a combination thereof.

20. The wind turbine of claim 15, wherein the at least one mounting element is securely connected to the at least one support element by at least one pin connection.

21. The wind turbine of claim 20, wherein the thickness of the at least one support element is between 80mm and 120 mm.

22. A method of assembling a wind turbine according to any of claims 1-21, wherein the method comprises the steps of:

-providing a generator rotor, wherein the rotor comprises at least a rotor structure,

-arranging a rotor back iron relative to the rotor structure,

-determining the position of at least one support element with respect to the rotor structure and the back iron,

-mounting a first end of the at least one support element to the back iron and further mounting a second end of the at least one support element to the rotor structure, wherein the at least one support element extends in an axial direction defined by the rotor and is provided between a side surface of the back iron and a corresponding side surface of the rotor structure, wherein the at least one support element is arranged at an angle with respect to a tangential direction of at least one of the side surface and the corresponding side surface.

23. The method of claim 22, wherein the first or second end is mounted to a back iron or rotor structure prior to positioning the back iron relative to the rotor structure.

24. The method of claim 22, further comprising the step of:

-arranging at least one beam-like element on at least one of said side surface and the corresponding side surface and positioning at least one of the first end and the second end with respect to said at least one beam-like element.

25. The method of claim 24, wherein the at least one beam-like element and at least one of the first and second ends are securely connected using a mounting means or an adhesive means or a combination thereof.

26. The method of claim 22, wherein the step of determining the position of at least one support element comprises arranging a plurality of support elements in an axial direction defined by the rotor.

27. The method of claim 26, further comprising the step of:

-providing at least one mounting element on at least one of the first end and the second end of each of the plurality of support elements.

28. The method of claim 27, wherein the at least one mounting element is fixedly attached to at least one of the first and second ends by at least one pin connection.

29. The method of claim 26, further comprising the step of:

-positioning the at least one first support element relative to the direction of rotation of the rotor such that it extends substantially in one direction, an

30. The method of claim 26, wherein at least one of the plurality of support elements intersects at least one other support element.

31. The method of claim 22, wherein at least one of the at least one support element, the at least one beam-like element and the at least one mounting element is manufactured by pultrusion or extrusion.